This invention relates to microminiature tapered structures and, more particularly, to all-metal structures having ultra-sharp tips.
Microminiature tapered structures have been proposed for use in a variety of applications of practical importance. Thus, for example, such structures in the form of field-emitter cathode tips have been suggested for use in matrix display devices, in scanning electron microscopes and in traveling wave tubes. These tips can also be employed in scanning tunneling microscopes, in atomic force microscopes, as biological probes and as electrodes in a variety of solid state devices.
In a copending commonly assigned application, Ser. No. 551,771, filed July 12, 1990, there is described a technique for making a substantially uniform array of tapered silicon structures, each having a tip that exhibits a radius of curvature of 10 nanometers or less. Although silicon tips made by that technique are advantageous for use in many applications, there are other applications of the type mentioned earlier above in which all-metal tips having the same sharpness and uniformity would be preferred. Relative to silicon, such all-metal tips would provide enhanced mechanical strength, better electrical and thermal conductivity and a different chemical reactivity. It was recognized therefore that all-metal tips of this type, if available, would in many cases provide a basis for improved device performance.